Improper access control in Unbound - CVE-2026-55708

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Main Vulnerability Database Vulnerabilities #VU139224

Improper access control in Unbound - CVE-2026-55708

Published: July 23, 2026


Vulnerability identifier: #VU139224
CSH Severity: Low
CVSS v4: 5.3 [CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-55708
CWE-ID: CWE-284
Exploitation vector: Remote access
Exploit availability: No public exploit available

Vulnerability details

The vulnerability allows a remote user to bypass local DNS policy protections.

The vulnerability exists due to improper access control in the unbound-control view_local_data and view_local_datas command handling when creating local zones for an already configured named view with no local data. A remote user can invoke the control interface to bypass local DNS policy protections.

Queries for default-protected names from clients mapped to the affected view may be forwarded to the public DNS instead of being answered locally.


Affected software

Unbound
Debian Linux
SUSE Linux Enterprise Server 15 SP5
SUSE Linux Enterprise Server 15 SP4
SUSE Linux Enterprise Server 15 SP6
SUSE Linux Enterprise Server for SAP Applications 15
SUSE Linux Enterprise High Performance Computing 15
SUSE Linux Enterprise High Performance Computing ESPOS 15
SUSE Linux Enterprise Server 15
SUSE Linux Enterprise High Performance Computing LTSS 15
SUSE Linux Enterprise Desktop 15
SUSE Linux Enterprise Real Time 15
SUSE Linux Enterprise Micro
Basesystem Module
SUSE Package Hub 15
openSUSE Leap
openEuler
Anolis OS
Fedora
unbound
python3-unbound
unbound-debuginfo
unbound-debugsource
unbound-devel
unbound-help
unbound-libs
unbound-anchor
unbound-utils
unbound-anchor-debuginfo
libunbound8
libunbound8-debuginfo
unbound-python-debuginfo
unbound-munin
unbound-python
libunbound-devel-mini-debuginfo
libunbound-devel-mini-debugsource
libunbound-devel-mini
unbound (Debian package)

How to mitigate CVE-2026-55708

Install security update from vendor's website.

Unbound - update to 1.25.2
unbound - addressed in versions 1.11.0-25, 1.13.2-25, 1.17.1-19, 1.17.1-20
python3-unbound - addressed in versions 1.11.0-25, 1.13.2-25, 1.17.1-19, 1.17.1-20
unbound-debuginfo - addressed in versions 1.11.0-25, 1.13.2-25, 1.17.1-19, 1.17.1-20
unbound-debugsource - addressed in versions 1.11.0-25, 1.13.2-25, 1.17.1-19, 1.17.1-20
unbound-devel - addressed in versions 1.11.0-25, 1.13.2-25, 1.17.1-19, 1.17.1-20
unbound-help - addressed in versions 1.11.0-25, 1.13.2-25, 1.17.1-19, 1.17.1-20
unbound-libs - addressed in versions 1.11.0-25, 1.13.2-25, 1.17.1-19, 1.17.1-20
unbound-anchor - addressed in versions 1.13.2-25, 1.17.1-19, 1.17.1-20
python3-unbound - update to 1.17.1-16
unbound - update to 1.17.1-16
unbound-anchor - update to 1.17.1-16
unbound-devel - update to 1.17.1-16
unbound-libs - update to 1.17.1-16
unbound-utils - update to 1.17.1-16
unbound-utils - addressed in versions 1.17.1-19, 1.17.1-20
unbound - update to 1.25.2-1.fc43
unbound-debuginfo - addressed in versions 1.25.2-150100.10.28.1, 1.25.2-150600.23.19.1
unbound-anchor-debuginfo - addressed in versions 1.25.2-150100.10.28.1, 1.25.2-150600.23.19.1
unbound-debugsource - addressed in versions 1.25.2-150100.10.28.1, 1.25.2-150600.23.19.1
unbound-anchor - addressed in versions 1.25.2-150100.10.28.1, 1.25.2-150600.23.19.1
libunbound8 - addressed in versions 1.25.2-150100.10.28.1, 1.25.2-150600.23.19.1
libunbound8-debuginfo - addressed in versions 1.25.2-150100.10.28.1, 1.25.2-150600.23.19.1
unbound-devel - addressed in versions 1.25.2-150100.10.28.1, 1.25.2-150600.23.19.1
unbound-python-debuginfo - update to 1.25.2-150600.23.19.1
unbound-munin - update to 1.25.2-150600.23.19.1
unbound-python - update to 1.25.2-150600.23.19.1
unbound - update to 1.25.2-150600.23.19.1
libunbound-devel-mini-debuginfo - update to 1.25.2-150600.23.19.1
libunbound-devel-mini-debugsource - update to 1.25.2-150600.23.19.1
libunbound-devel-mini - update to 1.25.2-150600.23.19.1
unbound (Debian package) - update to 1.26.1-0+deb13u1

External References

Related Security Bulletins